HomeMy WebLinkAboutKMART PLAZA, FULLER'S TEXACO - PDP - 38-97A - REPORTS - DRAINAGE REPORT91
VICINITY MAP
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100yr = 10.73 c.f.s.. There will be ponding to elevation 5018.5 at the existing inlet. The
development of this site will not significantly increase the runoff to the existing inlet. It will not
raise the ponding at the inlet. All existing and proposed buildings are above the highwater of the
ponding.
EROSION CONTROL: The site is in a moderate rainfall and wind zone. A silt fence will be
placed along the North, East and South sides of the Fuller Texaco site. A gravel filter will be
placed around the existing area inlet just North of the site. 7,500 square feet of gravel base will
be. retained on the site for a staging area and to meet the erosion control effectiveness
requirements. The remainder of the site will be disturbed for the new grading. The foundations
for the convenience store and car wash will be constructed soon after the asphalt is removed.
Due to the proposed gasoline pumps on the site and the possibility of a gasoline spill, the City
of Fort Collins' requirements include a plan of containment of the spill. Therefore we have
designed a distributing gate in the existing area inlet that can be closed in case of a spill. All of the
storm water from the site flows to the inlet and any gasoline will also flow to the area inlet. The
gate is a simple sliding galvanized metal plate that can be lowered to block any gasoline from
discharging from the inlet.
The runoff calculations, the erosion control calculations and the erosion control cost estimate
are enclosed as a part of the report. The Grading, Drainage and Erosion Control Plan is also
enclosed.
This drainage report and the design of the drainage system are in compliance with the City of
Fort Collins Storm Drainage specifications and criteria. If you have any questions regarding this
report, please call.
Sincerely,
6ah".k, a.
Richard A. Rutherford, P.E. & L.S.
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STEWART&kSSOCIATES
Consulting Engineers and Surveyors
June 5, 1998
Mr. Basil Hamdan
Storm Water Utility
City of Fort Collins
P.O. Box 580
Fort Collins, CO 80522
Dear Basil,
The following is the Final Drainage Report for Fuller Texaco which is a 0.59 acre site in the
K-Mart Plaza, which is in the Spring Creek Basin.. The site is located in the existing K-Mart
parking lot. The site is being developed for a convenience store with gasoline pumps.and a car
wash. The site is directly West of the existing Jiffy Lube at the Northwest comer of South
College Avenue and Drake Road. There will be cross access between the site and the Jiffy Lube
site.
The existing site is existing asphalt and landscaped islands. The site drains from South to
North to an existing area inlet. The runoff sheet flows to the inlet. There is an area West of the
site that also drains to the existing inlet. The historic runoff coefficient for the site is 0.81 and the
historic runoff rates are Q 2yr = 1.36 c.f.s., Q 10yr = 1.95 c.f.s. and Q 100yr. = 4.23 c.f.s.
The developed runoff coefficient for the site is 0.86 and the developed runoff rates are Q 2yr
= 1.52 c.f.s., Q 10yr = 2.63 c.f.s. and Q 100 yr. = 4.23 c.f.s.
The storm drainage specifications require that on site detention of the runoff between the two
year historic rate and the 100 year developed rate be provided. The historic and developed 100yr.
Rate of runoff are the same. Therefore we are not proposing to have on -site detention. None of
the K-Mart Plaza has on -site storm water detention.
The capacity of the area inlet grate is 6.05 c.£s. The storm drain out of the inlet is a 15 inch
diameter corrugated metal pipe with a slope of 0.45%. The capacity of the storm drain is 2.4
c.f.s. The runoff rates for the entire subbasin are Q 2yr = 3.34 c.f.s., Q 10yr = 5.81 c.f.s. and Q
James H. Stewart
and Associates, Inc.
103 S. Meldrum Street
P.O. Box
Ft. Collins, COC80522
970/482-9331
Fax 970/482-9382
Table of Contents
1 - 2 Text of Report
3 Vicinity Map
4 - 9 Runoff Calculations
10- 13 Erosion Control Calculations
Pocket Grading, Drainage & Erosion Control Plan
FINAL DRAINAGE REPORT
FOR
FULLER TEXACO
IN
SPRING CREEK BASIN
PREPARED FOR
RALPH FULLER
JUNE 591998
PREPARED BY
STEWART & ASSOCIATES, INC.
103 SOUTH MELDRUM STREET
FORT COLLINS, COLORADO 80521
970/482-9331